Helmholtz energy Definition and 12 Threads

Summary:: Gibbs and Helmholtz energies calculations for heating an ideal gas at constant volume I am solving a problem involving an ideal gas that undergoes several chained changes of state. One of the steps asks to calculate the change in Gibbs Energy (DeltaG) and Helmholtz energy (Delta A)...

Hello, so first of all I want to clarify that english is not my first lenguage, so I'm really sorry for possible future errors. Second, this is a problem from my physical chemistry class, and I'm not sure where it fits better, if here or in the physics homework help, I'm sorry :( So, I don't...

Homework Statement This is a state ecuation of a gas: PV=AT+B/V, where A and B there are constants. First: Demonstrate that ##c_V## depends only of T Second: Find U(T,V) and S(T,V) Homework Equations ##\left(\frac{\partial U}{\partial S}\right)_V=T\text{ (1)}## ##\left(\frac{\partial...

Homework Statement Show that for a reaction occurring at constant T and V, F is minimized at equilibrium. Homework Equations ##F=U-TS## ##TdS=dU+pdV-\mu dN## The Attempt at a Solution ##dF=dU-d(TS)=dU-TdS-SdT=dU-dU -pdV+ \mu dN -S dT=-pdV - SdT + \mu dN##. At constant T and V this reduces to...

Hey, The helmholtz energy is supposed to have a minimum when the entropy has a maximum value. Does anyone knows the derivation for this statement?

The problem is : a) Find Helmholtz free energy F(V, T) of a simple solid. b) Use the result of part a) to verify that (∂F/∂T)v and (∂F/∂V)T are consistent with S(T, V) and P(V, T) in equation P=a0T-b0ln(V/V0) I know: Helmholtz free energy is F=U-TS and dF=-SdT-PdV S=-((∂F/∂T)v)...

Homework Statement The 4 fundamental equations of thermodynamics are: dE = TdS - PdV dH = TdS + VdP dG = VdP - SdT dA = - PdV - SdT Supose a gas obeys the equation of state P = \frac{nRT}{V} - \frac{an^{2}}{V^{2}} Use one of the fundamental equations to find the change in Helmholtz energy...

Homework Statement Define the Helmholtz free energy as F=E-TS. Show that the internal energy E=-T2\frac{∂}{∂T}(\frac{F}{T})V Homework Equations S=(\frac{∂F}{∂T})V Perhaps \beta=\frac{1}{\tau} and \tau=kBT The Attempt at a Solution E = F+TS E = F+T(\frac{∂F}{∂T})V . . . (some...

I'm confused about the condition for spontaneity for the Helmholtz energy. My textbook (McQuarrie, "Physical Chemistry") derives the conditions as follows. We start with the combined law of thermodynamics: dU = δq + δw ≤ TdS – PdV since δq/T ≤ dS dU – TdS + PdV ≤ 0 For a process at...

Hi I'm trying to calculate Helmholtz free energy from definition \frac{\partial A}{\partial T}=\frac{\partial}{\partial T}(kT\mathrm{ln}\; Z). First \langle E\rangle=\sum\limits_i p_i E_i=\sum\limits_i E_i\frac{g_i e^{-\beta E_i}}{Z}=\frac{1}{Z}\sum\limits_i E_i g_i e^{-\beta...

I'm having some trouble understanding this concept. Why is it that you sometimes can get heat for free from the environment? Like suppose you have a system, on which you make an energyconsuming proces which creates entropy. Then you subtract TΔS because apparently heat can enter when the entropy...

Homework Statement Explain why the formula (dF/dV)=-P , where T and N are constant variables , makes intuitive sense, by discussing graphs of F vs. V with different slopes. Homework Equations The Attempt at a Solution dF=SdT-PdV+mu*dN dT and DN are zero since T and N are...